diff options
Diffstat (limited to '')
| -rw-r--r-- | drivers/vhost/scsi.c | 17 | ||||
| -rw-r--r-- | drivers/vhost/vhost.c | 114 | ||||
| -rw-r--r-- | drivers/vhost/vhost.h | 2 |
3 files changed, 105 insertions, 28 deletions
diff --git a/drivers/vhost/scsi.c b/drivers/vhost/scsi.c index 282aac45c6..f34f9895b8 100644 --- a/drivers/vhost/scsi.c +++ b/drivers/vhost/scsi.c @@ -497,10 +497,8 @@ again: vq_err(vq, "Faulted on vhost_scsi_send_event\n"); } -static void vhost_scsi_evt_work(struct vhost_work *work) +static void vhost_scsi_complete_events(struct vhost_scsi *vs, bool drop) { - struct vhost_scsi *vs = container_of(work, struct vhost_scsi, - vs_event_work); struct vhost_virtqueue *vq = &vs->vqs[VHOST_SCSI_VQ_EVT].vq; struct vhost_scsi_evt *evt, *t; struct llist_node *llnode; @@ -508,12 +506,20 @@ static void vhost_scsi_evt_work(struct vhost_work *work) mutex_lock(&vq->mutex); llnode = llist_del_all(&vs->vs_event_list); llist_for_each_entry_safe(evt, t, llnode, list) { - vhost_scsi_do_evt_work(vs, evt); + if (!drop) + vhost_scsi_do_evt_work(vs, evt); vhost_scsi_free_evt(vs, evt); } mutex_unlock(&vq->mutex); } +static void vhost_scsi_evt_work(struct vhost_work *work) +{ + struct vhost_scsi *vs = container_of(work, struct vhost_scsi, + vs_event_work); + vhost_scsi_complete_events(vs, false); +} + static int vhost_scsi_copy_sgl_to_iov(struct vhost_scsi_cmd *cmd) { struct iov_iter *iter = &cmd->saved_iter; @@ -1509,7 +1515,8 @@ vhost_scsi_send_evt(struct vhost_scsi *vs, struct vhost_virtqueue *vq, } llist_add(&evt->list, &vs->vs_event_list); - vhost_vq_work_queue(vq, &vs->vs_event_work); + if (!vhost_vq_work_queue(vq, &vs->vs_event_work)) + vhost_scsi_complete_events(vs, true); } static void vhost_scsi_evt_handle_kick(struct vhost_work *work) diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c index 8995730ce0..1740a5f1f3 100644 --- a/drivers/vhost/vhost.c +++ b/drivers/vhost/vhost.c @@ -276,21 +276,36 @@ void vhost_vq_flush(struct vhost_virtqueue *vq) EXPORT_SYMBOL_GPL(vhost_vq_flush); /** - * vhost_worker_flush - flush a worker + * __vhost_worker_flush - flush a worker * @worker: worker to flush * - * This does not use RCU to protect the worker, so the device or worker - * mutex must be held. + * The worker's flush_mutex must be held. */ -static void vhost_worker_flush(struct vhost_worker *worker) +static void __vhost_worker_flush(struct vhost_worker *worker) { struct vhost_flush_struct flush; + if (!worker->attachment_cnt || worker->killed) + return; + init_completion(&flush.wait_event); vhost_work_init(&flush.work, vhost_flush_work); vhost_worker_queue(worker, &flush.work); + /* + * Drop mutex in case our worker is killed and it needs to take the + * mutex to force cleanup. + */ + mutex_unlock(&worker->mutex); wait_for_completion(&flush.wait_event); + mutex_lock(&worker->mutex); +} + +static void vhost_worker_flush(struct vhost_worker *worker) +{ + mutex_lock(&worker->mutex); + __vhost_worker_flush(worker); + mutex_unlock(&worker->mutex); } void vhost_dev_flush(struct vhost_dev *dev) @@ -298,15 +313,8 @@ void vhost_dev_flush(struct vhost_dev *dev) struct vhost_worker *worker; unsigned long i; - xa_for_each(&dev->worker_xa, i, worker) { - mutex_lock(&worker->mutex); - if (!worker->attachment_cnt) { - mutex_unlock(&worker->mutex); - continue; - } + xa_for_each(&dev->worker_xa, i, worker) vhost_worker_flush(worker); - mutex_unlock(&worker->mutex); - } } EXPORT_SYMBOL_GPL(vhost_dev_flush); @@ -392,7 +400,7 @@ static void vhost_vq_reset(struct vhost_dev *dev, __vhost_vq_meta_reset(vq); } -static bool vhost_worker(void *data) +static bool vhost_run_work_list(void *data) { struct vhost_worker *worker = data; struct vhost_work *work, *work_next; @@ -417,6 +425,40 @@ static bool vhost_worker(void *data) return !!node; } +static void vhost_worker_killed(void *data) +{ + struct vhost_worker *worker = data; + struct vhost_dev *dev = worker->dev; + struct vhost_virtqueue *vq; + int i, attach_cnt = 0; + + mutex_lock(&worker->mutex); + worker->killed = true; + + for (i = 0; i < dev->nvqs; i++) { + vq = dev->vqs[i]; + + mutex_lock(&vq->mutex); + if (worker == + rcu_dereference_check(vq->worker, + lockdep_is_held(&vq->mutex))) { + rcu_assign_pointer(vq->worker, NULL); + attach_cnt++; + } + mutex_unlock(&vq->mutex); + } + + worker->attachment_cnt -= attach_cnt; + if (attach_cnt) + synchronize_rcu(); + /* + * Finish vhost_worker_flush calls and any other works that snuck in + * before the synchronize_rcu. + */ + vhost_run_work_list(worker); + mutex_unlock(&worker->mutex); +} + static void vhost_vq_free_iovecs(struct vhost_virtqueue *vq) { kfree(vq->indirect); @@ -631,9 +673,11 @@ static struct vhost_worker *vhost_worker_create(struct vhost_dev *dev) if (!worker) return NULL; + worker->dev = dev; snprintf(name, sizeof(name), "vhost-%d", current->pid); - vtsk = vhost_task_create(vhost_worker, worker, name); + vtsk = vhost_task_create(vhost_run_work_list, vhost_worker_killed, + worker, name); if (!vtsk) goto free_worker; @@ -664,22 +708,37 @@ static void __vhost_vq_attach_worker(struct vhost_virtqueue *vq, { struct vhost_worker *old_worker; - old_worker = rcu_dereference_check(vq->worker, - lockdep_is_held(&vq->dev->mutex)); - mutex_lock(&worker->mutex); - worker->attachment_cnt++; - mutex_unlock(&worker->mutex); + if (worker->killed) { + mutex_unlock(&worker->mutex); + return; + } + + mutex_lock(&vq->mutex); + + old_worker = rcu_dereference_check(vq->worker, + lockdep_is_held(&vq->mutex)); rcu_assign_pointer(vq->worker, worker); + worker->attachment_cnt++; - if (!old_worker) + if (!old_worker) { + mutex_unlock(&vq->mutex); + mutex_unlock(&worker->mutex); return; + } + mutex_unlock(&vq->mutex); + mutex_unlock(&worker->mutex); + /* * Take the worker mutex to make sure we see the work queued from * device wide flushes which doesn't use RCU for execution. */ mutex_lock(&old_worker->mutex); - old_worker->attachment_cnt--; + if (old_worker->killed) { + mutex_unlock(&old_worker->mutex); + return; + } + /* * We don't want to call synchronize_rcu for every vq during setup * because it will slow down VM startup. If we haven't done @@ -690,6 +749,8 @@ static void __vhost_vq_attach_worker(struct vhost_virtqueue *vq, mutex_lock(&vq->mutex); if (!vhost_vq_get_backend(vq) && !vq->kick) { mutex_unlock(&vq->mutex); + + old_worker->attachment_cnt--; mutex_unlock(&old_worker->mutex); /* * vsock can queue anytime after VHOST_VSOCK_SET_GUEST_CID. @@ -705,7 +766,8 @@ static void __vhost_vq_attach_worker(struct vhost_virtqueue *vq, /* Make sure new vq queue/flush/poll calls see the new worker */ synchronize_rcu(); /* Make sure whatever was queued gets run */ - vhost_worker_flush(old_worker); + __vhost_worker_flush(old_worker); + old_worker->attachment_cnt--; mutex_unlock(&old_worker->mutex); } @@ -754,10 +816,16 @@ static int vhost_free_worker(struct vhost_dev *dev, return -ENODEV; mutex_lock(&worker->mutex); - if (worker->attachment_cnt) { + if (worker->attachment_cnt || worker->killed) { mutex_unlock(&worker->mutex); return -EBUSY; } + /* + * A flush might have raced and snuck in before attachment_cnt was set + * to zero. Make sure flushes are flushed from the queue before + * freeing. + */ + __vhost_worker_flush(worker); mutex_unlock(&worker->mutex); vhost_worker_destroy(dev, worker); diff --git a/drivers/vhost/vhost.h b/drivers/vhost/vhost.h index 9e942fcda5..dc94e6a7d3 100644 --- a/drivers/vhost/vhost.h +++ b/drivers/vhost/vhost.h @@ -28,12 +28,14 @@ struct vhost_work { struct vhost_worker { struct vhost_task *vtsk; + struct vhost_dev *dev; /* Used to serialize device wide flushing with worker swapping. */ struct mutex mutex; struct llist_head work_list; u64 kcov_handle; u32 id; int attachment_cnt; + bool killed; }; /* Poll a file (eventfd or socket) */ |